U.S. patent number 10,328,648 [Application Number 15/329,670] was granted by the patent office on 2019-06-25 for textured die having blocks for manufacturing a textured mould for moulding and vulcanizing tires.
This patent grant is currently assigned to COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN. The grantee listed for this patent is COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN, MICHELIN RECHERCHE ET TECHNIQUE S.A.. Invention is credited to Bernard Villeneuve.
United States Patent |
10,328,648 |
Villeneuve |
June 25, 2019 |
Textured die having blocks for manufacturing a textured mould for
moulding and vulcanizing tires
Abstract
Die (1) representing a tread pattern model for a tread of a tire
to be molded. The die is made up of a plurality of blocks (2)
separated by grooves (4), at least a part of the die having
surfaces provided with textures (5).
Inventors: |
Villeneuve; Bernard
(Clermont-Ferrand, FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN
MICHELIN RECHERCHE ET TECHNIQUE S.A. |
Clermont-Ferrand
Granges-Paccot |
N/A
N/A |
FR
CH |
|
|
Assignee: |
COMPAGNIE GENERALE DES
ETABLISSEMENTS MICHELIN (Clermont-Ferrand, FR)
|
Family
ID: |
51726568 |
Appl.
No.: |
15/329,670 |
Filed: |
July 21, 2015 |
PCT
Filed: |
July 21, 2015 |
PCT No.: |
PCT/IB2015/001213 |
371(c)(1),(2),(4) Date: |
January 27, 2017 |
PCT
Pub. No.: |
WO2016/016699 |
PCT
Pub. Date: |
February 04, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170225419 A1 |
Aug 10, 2017 |
|
Foreign Application Priority Data
|
|
|
|
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Jul 30, 2014 [FR] |
|
|
14 01753 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29D
30/0606 (20130101); B29C 33/3842 (20130101); B29C
33/3892 (20130101); B29C 33/424 (20130101); B29C
33/3878 (20130101); B29D 2030/0612 (20130101); B29D
2030/0616 (20130101); B22C 7/00 (20130101) |
Current International
Class: |
B29D
30/06 (20060101); B29C 33/38 (20060101); B22C
7/00 (20060101); B29C 33/42 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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WO 95/18022 |
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Jul 1995 |
|
WO |
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WO 99/48674 |
|
Sep 1999 |
|
WO |
|
WO 2010/072961 |
|
Jul 2010 |
|
WO |
|
WO 2010/096072 |
|
Aug 2010 |
|
WO |
|
Primary Examiner: Mackey; James P
Attorney, Agent or Firm: Cozen O'Connor
Claims
The invention claimed is:
1. A die representing a tread pattern model for a tread of a tire
to be moulded, said die comprising: a base portion having a
plurality of protruding sections spaced apart from one another to
define protrusion spacings therebetween, each protruding section
having an end section with a flat end surface; a plurality of
blocks each arranged in one of the protrusion spacings, or adjacent
to a single one of the protruding sections, the blocks being
arranged so that at least a portion of sidewalls of each block
protrudes above the end section or sections of the adjacent
protruding section or sections of the base portion; and a plurality
grooves are arranged between the blocks, each groove being defined
by the end section of the one of the protruding sections of the
base portion, as a groove bottom, and adjacent sidewalls of the
blocks arranged in the protrusion spacings on each side of the
respective protruding section and protruding above the end section,
wherein at least one of the end sections is provided with first
textures, and wherein at least one sidewall of at least one of the
blocks has a substantially flat surface provided with second
textures.
2. The die according to claim 1, wherein the wherein the first
textures are arranged in the bottom of the grooves.
3. The die according to claim 1, wherein the sidewalls of the
blocks are bevelled and the bevelling includes the second
textures.
4. The die according to claim 1, wherein at least one of the first
and second textures comprises a plurality of recessed or protruding
elements formed integrally with said die.
5. The die according to claim 1, wherein all or some of the first
and second textures are formed by cones distributed through the
texture at a density at least equal to one cone per square
millimeter (mm.sup.2), each said cone having a mean cross section
of between 0.0005 mm.sup.2 and 1 mm.sup.2.
6. The die according to claim 1, wherein all or some of the first
and second textures are substantially mutually parallel striations,
the spacing of the striations in the pattern being at most equal to
0.5 mm, each said striation having a mean width of between 0.02 mm
and 0.5 mm.
7. The die according to claim 1, wherein all or some of the first
and second textures form parallelepipeds having a side length of
between 0.05 mm and 0.5 mm and a height of between 0.05 mm and 0.5
mm, the distance between two adjacent parallelepipeds in the
texture being between 0.05 mm and 0.5 mm.
8. The die according to claim 4, wherein the protruding elements
form strands, said strands being distributed through the pattern at
a density at least equal to one strand per square millimeter
(mm.sup.2), each said strand having a mean cross section of between
0.0005 mm.sup.2 and 1 mm.sup.2.
9. The die according to claim 4, wherein the protruding elements
form mutually parallel blades, the spacing of the blades in the
pattern being at most equal to 0.5 mm, each said blade having a
mean width of between 0.02 mm and 0.5 mm.
10. The die according to claim 4, wherein the recessed or
protruding elements exhibit mutually variable shapes and
distances.
11. A method for manufacturing a mould for moulding and vulcanizing
tires, comprising the steps of: manufacturing a die according to
claim 1; manufacturing, from the die, a mould corresponding to the
negative form of the tire to be moulded, made of flexible material;
manufacturing, from the mould made of flexible material, a die made
of brittle material, corresponding to the profile of the tire to be
moulded; manufacturing, from the brittle material die, a mould
corresponding to the negative form of the tire to be moulded, made
of metal material; and removing the brittle material die so as to
release the metal mould obtained.
12. The manufacturing method according to claim 11, wherein the
textures of the dies are realized by 3D printing or laser
machining, with the aid of punches, or by selective fusion of metal
powder, or by electrical discharge machining.
13. The manufacturing method of claim 11, wherein said flexible
material is silastene and said brittle material is plaster.
Description
RELATED APPLICATIONS
This is a U.S. National Phase Application under 35 USC 371 of
International Application PCT/IB2015/001213 filed on Jul. 21,
2015.
This application claims the priority of French application no.
1401753 filed Jul. 30, 2014, the entire content of which is hereby
incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to a die representing a tread pattern
model for a tread of a tire to be moulded. It also provides a
method for manufacturing a mould for moulding and vulcanizing
tires.
BACKGROUND OF THE INVENTION
The document WO2010072961 describes a die for manufacturing a tire
mould, said die being produced by laser sintering. By virtue of
this manufacturing method, the part to be manufactured can be
modelled by computer and manufactured easily on the basis of this
modelling. However, the document describes a one-piece element, the
design and manufacture of which have to be revised as soon as an
architectural or dimensional change is made to the final product to
be moulded. Moreover, the large parts manufactured by this method
are relatively expensive to produce, mainly because the base
materials are specific to the manufacturing method.
The application WO2010096072 relates to a cast moulding method,
useful in the context of manufacturing micro-textured objects. The
introduction of a plurality of micro-patterns into the surface of
an object makes it possible to add certain features to the
micro-textured object, for instance an increase in hydrophobicity.
Some of the casting and moulding methods described in that document
make it possible to arrive at the manufacture of objects that have
both macro- and micro-features, for instance micro-patterns inside
or on zones having macro-features. The method described therein is
used exclusively on curved surfaces.
The document US20020176792 proposes a method for manufacturing a
mould segment for a pneumatic tire having a tread surface made of
porous metal. A model of an annular tire segment made of refractory
material is formed in this mould, with segments of the tire model
which are used to fashion and form each segment of the tire mould
from powdered metal, and by means of the application of heat and
pressure for sintering the metal as per the tire model. Blades can
be mounted in the segments of the tire model in order to mould
slits in the tread of the tire.
There is thus a need for a solution that makes it possible to
produce dies at a lower cost, making it possible to take into
account both the changes to the end product and the increasingly
stringent requirements relating to the characteristics of shapes,
dimensions and precision of the various zones of the dies.
The invention provides various technical means for overcoming these
various disadvantages.
SUMMARY OF THE INVENTION
First of all, a first object of the invention is to provide a die
representing a tread pattern model for a tread of a tire having
elements with highly complex textures and/or very small dimensions
with very high precision and at an attractive cost.
Another object of the invention is to provide a method for
manufacturing moulds for moulding and vulcanizing tires, making it
possible to obtain several moulds that each exhibit a high level of
quality, at an advantageous cost.
To this end, one aspect of the invention relates to a die
representing a tread pattern model for a tread of a tire to be
moulded, said die being made up of a plurality of blocks separated
by grooves, the grooves being formed by substantially flat
surfaces, at least some of these substantially flat surfaces being
provided with textures.
With such an architecture, it is possible to produce a die that
bears very high precision textured surfaces, even if the textured
surfaces are difficult to access. Moreover, a single die makes it
possible to manufacture several moulds, making the concept
particularly advantageous.
According to one advantageous embodiment, the substantially flat
surfaces provided with textures are in the bottom of grooves.
According to another advantageous embodiment, the substantially
flat surfaces provided with textures are on the walls of
blocks.
Advantageously, the textures are arranged on tops of tread
patterns.
Advantageously, the walls of blocks are bevelled.
Also advantageously, the textures comprise a plurality of recessed
or protruding elements formed integrally with said die.
According to another variant embodiment, all or some of the
textures are formed by cones distributed through the texture at a
density at least equal to one cone per square millimeter
(mm.sup.2), each cone having a mean cross section of between 0.0005
mm.sup.2 and 1 mm.sup.2.
According to another variant embodiment, all or some of the
textures are substantially mutually parallel striations, the
spacing of the striations in the pattern being at most equal to 0.5
mm, each striation having a mean width of between 0.02 mm and 0.5
mm.
According to yet another embodiment, all or some of the textures
form parallelepipeds having a side length of between 0.05 mm and
0.5 mm and a height of between 0.05 mm and 0.5 mm, the distance
between two adjacent parallelepipeds in the texture being between
0.05 mm and 0.5 mm.
According to another embodiment, the protruding elements form
strands, said strands being distributed through the pattern at a
density at least equal to one strand per square millimeter
(mm.sup.2), each strand having a mean cross section of between
0.0005 mm.sup.2 and 1 mm.sup.2.
According to another variant embodiment, the protruding elements
form mutually parallel blades, the spacing of the blades in the
pattern being at most equal to 0.5 mm, each blade having a mean
width of between 0.02 mm and 0.5 mm.
According to another embodiment, the recessed or protruding
elements exhibit mutually variable shapes and distances.
According to yet another embodiment, the die is formed by
clustering of a plurality of blocks.
Another aspect of the invention provides a method for manufacturing
a mould for moulding and vulcanizing tires, comprising the steps
of: manufacturing a die as described above comprising at least one
groove formed by substantially flat surfaces, at least some of
these substantially flat surfaces being provided with textures;
manufacturing, from the die, a mould corresponding to the negative
form of the tire to be moulded, made of flexible material,
preferably silastene; manufacturing, from the mould made of
flexible material, a die made of brittle material, preferably
plaster, corresponding to the profile of the tire to be moulded;
manufacturing, from the brittle material die, a mould corresponding
to the negative form of the tire to be moulded, made of metal
material, preferably aluminium; removing the brittle material die
(for example by destroying the latter), so as to release the metal
mould obtained.
Advantageously, the textures of the dies are manufactured by 3D
printing or laser machining, with the aid of punches, or by
selective fusion of metal powder, or by electrical discharge
machining.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a perspective view of a portion of a die according to an
embodiment of the invention;
FIG. 1b is an enlarged view of a textured zone of the die in FIG.
1a;
FIG. 2 is a perspective view of an example of a punch that can be
used to produce the textured walls or zones of the die in FIG.
1a;
FIG. 3a shows the blocks of a die according to an embodiment of the
invention in a perspective view;
FIG. 3b shows one of the blocks from FIG. 3a in an enlarged
view;
FIGS. 4 to 9 illustrate various examples of types of texture that
are able to be arranged on a die according to an embodiment of the
invention;
FIG. 10 shows a diagram illustrating the main steps for
manufacturing a mould for moulding and vulcanizing a tire from a
die according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1a illustrates an example of an embodiment of a die 1
according to the invention. More specifically, the figure
illustrates a cross section through a die having a plurality of
blocks 2 separated by grooves 4. The blocks 2 can correspond for
example to tread pattern elements of the tire modelled by the die.
The die delimits a plurality of faces which correspond to portions
of the tread of the modelled tire. According to the invention, one
or more of these faces are provided with textures 5, as shown for
example in FIGS. 1a and 1b.
Moreover, the textures 5 can be arranged in different zones, at the
groove bottom, and/or on the walls of the blocks and/or on the
upper surface of the blocks. For example, the example in FIG. 1a
provides textures 5 at the groove bottom, continuing over the walls
of the blocks as far as the top of the blocks, covering portions of
the tops of blocks. In a variant that is not illustrated, the
textures continue over the entire top of at least some of the
blocks.
According to the embodiments, the die 1 can be made in one piece,
as illustrated in FIG. 1a, or by clustering a plurality of blocks
on a support, as in the example in FIG. 3a (where the support is
not illustrated in order to clearly show the blocks).
FIG. 2 illustrates an example of a punch 10 having zones or sectors
comprising textures 11 opposite to those to be realized on the die.
This type of punch is able to be used to realize the textures on a
die as illustrated in FIG. 1a. Depending on the parts to be
manufactured, notably on the number and the position of the
textures, only one or several textured zones are provided on the
punch. The textured zones of the punch are advantageously provided
on protruding section 9 that are specifically provided to bear the
textures to be transferred to the corresponding part. However, as
can be seen in FIG. 1b, some faces of the die 1 can have limited
access or be difficult to access, all the same. In such cases, the
shaping of the textured faces may prove tricky.
As mentioned above, FIG. 1a illustrates a perspective view of an
example of a die 1 obtained by bringing together a plurality of
blocks 2, FIG. 3a is a perspective view where only the blocks 2 are
shown in order to clearly highlight them. FIG. 3b is an enlarged
view of the right-hand block in FIG. 3a, said block being separated
from the others and repositioned so that the textured zone is
easily accessible. The provision of blocks 2 advantageously
manufactured independently of the rest of the die makes it possible
to manipulate them without restriction, in particular in order to
carry out any steps relating to the addition of textures to the
zones provided to this end. For example, in FIG. 3b, the textured
zone 5 is easily accessible for the shaping of the textures,
whether this be with the aid of a punch, by laser machining, or any
other method.
It can be seen that the blocks 2 make it possible to supply walls
or faces of grooves provided with very high precision textures,
even if the patterns are complex and/or have relatively small
dimensions. Moreover, since the textures are produced on separate
elements (the blocks), it is possible to provide manufacturing
conditions that are specifically tailored such that the levels of
quality and precision are ensured consistently on all of the
surfaces, at a particularly attractive cost. Finally, the concept
makes it possible to produce, from a single die body, architectural
variants in which the arrangements of textures can vary in order to
create a considerable number of variants at low cost. These
arrangements can provide textures of which the shapes and/or
dimensions and/or distributions can vary, depending on
requirements.
FIGS. 4 to 9 illustrate further examples of textures that can be
disposed on a die according to the invention. FIG. 4 illustrates an
embodiment in which the pattern has a plurality of strands 106. The
strands 106 are distributed in the pattern at a density at least
equal to one strand per mm.sup.2, each strand having a mean cross
section S of between 0.0005 mm.sup.2 and 1 mm.sup.2. It will be
noted that the mean cross section of each strand corresponds to the
mean of the cross sections S measured at regular intervals from the
base of the strand. The strands 106 have a conical overall shape
with a cross section that decreases over the height Hb of these
strands.
FIG. 5 illustrates an embodiment in which the pattern has a
plurality of mutually parallel blades 107, the spacing of the
blades 107 in the pattern being at most equal to 0.5 mm, each blade
107 having a mean width of between 0.02 mm and 0.5 mm. It will be
noted that the mean width corresponds to the mean of the widths I
measured at regular intervals over the height HI of the blade, the
height of each blade being between 0.05 and 0.5 mm. In another
variant embodiment, the pattern has a combination of strands 106
and/or blades 107.
The invention is not limited to the examples described and shown
and various modifications can be made thereto without departing
from its scope. Thus, according to another non-limiting variant
embodiment, the blades 107 from FIG. 5 can be discontinuous. They
have a flat part between one another. They can also have
cross-sectional differences between one another. In addition, the
blades can have curves or angles, notably along their length. They
can also have a variable length.
In the example in FIG. 6, the patterns have a parallelepipedal
cross section 108 having a side length C of between 0.05 mm and 0.5
mm and a height Hp of between 0.05 mm and 0.5 mm, the distance Dp
between two adjacent cavities in the texture being between 0.05 mm
and 0.5 mm. In a variant, the cross section of the patterns can be
circular or polygonal (for example hexagonal). With the square or
polygonal structures, it is possible to more easily organize the
elements with respect to one another so as to limit the surface
area of the intermediate zones between the elements.
In the variant in FIG. 7, the elements 109 have mutually variable
shapes and distances. This variant makes it possible to render the
details of the texture less visible.
FIG. 8 illustrates the pattern according to another non-limiting
variant embodiment. In this variant, the pattern is formed by a
plurality of cavities 112. The cavities 112 are in this case in the
form of cones which extend into the depth of the mould and open out
of the mould, forming circular openings 111. The cavities 112 thus
have a cross section which decreases with depth into the mould. It
will be noted that, in this variant, the openings 111 of the
cavities 112 are not in contact. The openings 111 are separated by
intermediate zones 113. Moreover, the openings 111 are distributed
regularly over the mould such that the distance d between each
opening of the pattern is similar overall.
FIG. 9 is an enlarged view of the pattern in FIG. 10. In this case,
all or some of the cavities have at least one wall 114 which, in
cross section, forms an angle .beta. of between 10.degree. and
60.degree. with respect to a direction Z perpendicular to the
pattern.
The die 1 according to the invention, the blocks 2 and in
particular the shaping of the textures 5 can be realized by 3D
printing, laser machining, with the aid of punches or by electrical
discharge machining. Such a die has the advantage of making it
possible to manufacture a plurality of moulds for moulding and
vulcanizing tires. By virtue of the textured die 1 serving as a
base model, the manufactured moulds are provided with textures
opposite to those of the die, giving the moulded tires textures
that match those of the base die, without having to provide a
specific subsequent machining step for the mould or for the tires.
This results in particularly advantageous ease of manufacture, and
lower costs.
However, this die cannot be used directly for industrially
manufacturing moulds for moulding and vulcanizing tires. This is
because, since the final mould is made of metal material, i.e.
non-flexible material, the initial die, which is also not flexible,
cannot generally serve to produce the final mould, since the two
elements combined would be difficult to separate. Therefore,
provision is made, in a known manner, to provide a set of
intermediate steps for passing from a rigid die to a flexible
intermediate mould, and then to a die that is easy to remove once
the final metal mould has been produced. These various steps are
illustrated in FIG. 10.
The functional flowchart in FIG. 10 shows the main steps in the
method according to the invention for manufacturing a mould for
moulding and vulcanizing a tire. In step 100, first of all, a die 1
is manufactured, having blocks 2 and textured walls 5, the shape
characteristics of which correspond to the tire to be moulded. The
blocks 2 are advantageously manufactured separately, under
conditions for shaping the textures, and then attached to the body
of the die. Fastening can take place by adhesive bonding, screwing,
or the like.
In step 101, a negative mould made of flexible material is produced
from this die. On account of the flexibility of the material, the
mould obtained can be removed easily from the die 1, which serves
both as a support and as a model therefor. In step 102, another die
is manufactured, this time from the mould made of flexible material
obtained in step 101. Since this die is intended to be sacrificed
in a subsequent step, provision is advantageously made to produce
the part from inexpensive material that is easy to destroy, for
example plaster. It should be noted that this die has a profile
corresponding to that of the initial die 1. Once the plaster die
has been obtained, this makes it possible to produce the final
metal mould (step 103). The two parts, namely the metal mould and
the brittle material die, are separated by breaking the die so as
to release the metal mould.
In this way, a metal mould which will make it possible to
faithfully reproduce the textures of the base die on the tires to
be manufactured is obtained.
The scope of protection of the invention is not limited to the
examples given hereinabove. The invention is embodied in each novel
characteristic and each combination of characteristics, which
includes every combination of any features which are stated in the
claims, even if this feature or combination of features is not
explicitly stated in the examples.
* * * * *